Local buses feeling fried by de-icer
The top maintenance official at the Roaring Fork Transit Agency says the deicer magnesium chloride has been wreaking havoc with many of the buses that run up and down Highway 82.
Wiring and electrical connections located below the splash line are particularly vulnerable to corrosion and meltdowns, causing heating systems to fail and automatic transmissions to take on lives of their own.
“We’ve had a lot of real strange shifting experiences with the transmissions on our articulates,” said Kenny Osier, RFTA’s director of maintenance.
Osier said RFTA maintenance crews have found themselves replacing plugs and wirings much more regularly since 1996, when the Colorado Department of Transportation made magnesium chloride its primary weapon in the annual war on ice.
“A lot more attention needs to be be paid to the maintenance of electrical connections,” Osier said. “We’ve run buses for 20 years and it was like, `Corrosion, what’s that?’ “
Magnesium chloride is a form of salt mined from the Great Salt Lake in Utah. Unlike its chemical cousin sodium chloride, more familiarly known as table salt, mag chloride is relatively easy to use as a liquid and can be combined with anticorrosive agents and water before being sprayed on icy road surfaces.
The problem with mag chloride from RFTA’s point of view begins when it works its way into a plug or some other connection. The mag chloride then drips into bundles of wires, causing individual wires to corrode and fail. Osier said that forces up the amperage and then the temperature in the wires that haven’t been corrupted, which melts the insulation and causes a short.
“We’ve actually seen plugs melt. It was a little shocking,” he said.
RFTA crews have also found corrosion on the bodies of some buses that are only a few years old, especially in areas immediately behind the tires.
“When buses are only four or five years old, and you start seeing structural corrosion, you have to ask yourself: This is what we can see. What can’t we see?” Osier said.
CDOT’s superintendent of maintenance, Ed Fink, confirmed that mag chloride has proven more corrosive than the old mix of sodium chloride, gravel and sand. But he defended the state’s use of the liquid deicer on the grounds it causes much less air pollution.
“We can’t go back and we can’t adopt a do-nothing approach,” he said.
Six million gallons of magnesium chloride will be spread on state highways this winter.
CDOT also experienced some maintenance problems when it started using magnesium chloride, especially with the tanker trunks used to spray it on the road surface. As at RFTA, the problems occurred with electrical connections and wiring on the underside of the trucks and in areas splashed by the tires. But Fink said CDOT trucks survive the winter mostly unscathed these days, thanks to some changes in wiring and maintenance practices.
“You talk to road guys and they love it. It clears the ice, which is their job,” said John Baker, a member of the Snowmass Village road maintenance crew.
Three years ago Snowmass Village became one of the first communities in the state to quit using mag chloride.
“We used it for a couple of winters and it was particularly corrosive, especially on wiring and electrical components,” said Dave Joiner, the town’s fleet supervisor.
The corrosion affected just about every kind of vehicle the town owns, from pickup trucks to buses. The town’s shuttle buses, which spend more time on the road each day than other town vehicles, were affected the most.
The electrical problems came as a surprise to Joiner, because his experience has been that the insulation on wiring can last as long as 20 or 30 years. The town decided to quit using mag chloride shortly after spending millions of dollars to rebuild Snowmelt Road, because a distributor admitted that it could have corrosive effects on concrete and the metal bars used to reinforce it.
The town now uses a deicer known as NAAC, which is considerably more expensive, but much friendlier to the town’s vehicle fleet. Joiner said the corrosion problems disappeared as soon as the switch was made.
Not every bus system and municipality has experienced the same trouble as RFTA and Snowmass Village, however.
Dean Shaklee, who oversees maintenance for the RTD bus system in Denver, said his buses haven’t had any electrical problems related to mag chloride. But he noted that the undercarriages of much of his fleet are washed on a nightly basis.
“They don’t put mag chloride down as much here as they do up there,” he added.
The fleet maintenance supervisor for the town of Avon, Dan Higgins, said there has been little trouble that can be attributed to mag chloride with either the town’s vehicles or the buses for three separate systems that are under his care.
As in Denver, all of the buses running in and between Avon and Beaver Creek and throughout Eagle County are washed every night. “We just moved into a new facility, but even before the move we never had trouble with mag chloride,” Higgins said.
RFTA’s Osier said that an undercarriage washing system is in the works at the new maintenance facility planned in Glenwood Springs. “We think if we wash it off, it will be OK,” he said.
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Don’t freak out if you see helicopters hovering over the Roaring Fork Valley backcountry or fixed-wing aircraft making repeated trips. It is part an annual wildlife study by Colorado Parks and Wildlife.